Gas-engine.



PATENTED MAY 12, 1908.

H. T. DUNBAR.

GAS ENGINE.

APPLICATION FILED MAR. 26, 1907.

2 SHEETS-SHEET 1.

PATENTED MAY 12, 1908.

H. T. DUNBAR.

GAS ENGINE.

APPLICATION FILED 11411.26, 1907.

2 SHEETS-SHEET 2.

1 W-Zrrcesses;

HARRIS T. DUNBAR, 0]? BUFFALO, NEW YORK.

GAS-ENGINE.

No. earner.

Specification of Letters Patent.

Patented May 12, 1908.

application filed March 26, 1907. Serial No. 364,622.

, To all whom it may concern:

Be it known that I, HARnrs T. DUNBAma citizen of the United States, residing at Buffalo, in the county of Erie and State of New York, have invented a new and useful improvement in Gas-Engines, of which the following is a specification.

This invention relates to a. two-stroke cycle gas or hydrocarbon engine.

in the t e of engine'as heretofore usually constructe the fuel inlet and exhaust ports are arranged on diametrically opposite sides of the cylinder and the piston is provided with a deflector, so that when the piston reaches the end ofits forward or working stroke and uncovers the inlet and exhaust ports the fuel-will be directed toward the ead of the cylinder and prevented from passing out through the exhaust port. hlle this answers the purpose sufficiently well to produce an operative engine, it is defective in that the dead or spent gases are never wholly removed from the cylinder and therefore impair the elficiency of the engine by becoming mixed with live or fresh gases. Furthermore, by drawing oil the hot dead gases on one side of the cylinder and admitting the cool live gases on the opposite side of the same, a difference in the expansion of the metal on 0 posite sides'of the cylinder is maintained w 'ch renders it impossible to kepip the piston tight for any length of time an results in loss of compression and output of ower.

The object of this invention is to so construct the engine that the, dead gases move simultaneously inward from all parts of the cylinder and escape at the center of the same while the live gases fill in the cylinder all around the escaping dead gases, thereby relieving the cylinder uniformly from the heat of the dead gases and also bringing the cool live gases uniformly in contact with all parts of the cylinder, whereby the incoming fuel is raised in temperature and its power producing capacity is increased and the temperature of the cylinder is reduced, causing the parts to operate more reliably and eflectively. In the accompanying drawings consisting of 2 sheets: Figure *1 is a vertical section of a two-stroke cycle engine embodying my, in,-

vention, the section being taken at the side of the piston. Fig. 2 is a fragmentary vertical section of the same taken centrally through the piston. Figs. 3and 4 are transverse sections, on an enlarged scale, in the correspondingly numbered lines in Fig. 2;

Similar letters of reference indicate corresponding parts throughout the several views. My invention is applicable to two-stroke cycle gas engines of various constructions as; to general organization. That shown in the drawings, as an example, consists of an upright cylinder A having its upper end closed by a head a, a closed or tight crank case 13 connected with the lower end of the cylinder and having a fuel supply pipe 12 containing a check valve b, a piston C reciprocating vertically in the cylinder, a crank shaft Dhaving a crank d within the crank case, a pitman E connecting the crank with the piston, a transfer passage or pipe F connected at one end with thecrank case while itsopposite end connects with a fuel orgas inlet port f opening into the'side of the cylinder adjacent to the point where the upper end of the piston terminates when the same reaches the end of its forward stroke, ma an exhaust port arranged in the side of the cylinder.

lncarrying out my inventionin the best form, it is preferable to locate the inlet and exhaust ports f, g horizontally in line and ad;

jacent to each other circumferentially on the I same side of the cylinder, as shown in Fig; 4. Within the upper or inner end of the piston the same is provided with an exhaust chamber or passage H- which has an upper or. inner opening h .extendin through the central part 0 the piston and p acing the exhaust chamher in communication with the central part of the space in the c linder, and a side opening it leading aterally through t e side of the piston and placin the exhaust chamber in communication with the exhaust port g during the last part of the forward stroke of the piston.

. 9n the inner end of the iston the same is provided with a spiral ue or guide-way which extends about three-fourths of a circle around the hopperopenin of the exhaust passage. The ottom t of t is flue or guideport or 1 way is inclined and its front or lower end is "inlet port receives the fresh gas upon entering the cylinder and which controls the course of the gas in thecylinder. The gas isadmitted into ward stroke of the piston at which time the ort f and.

rings the lower end of the guide ue or pas-' sage in line therewith. I

The relative arrangement of the fuel inlet and exhaust ports in the cylinder is such that during the last portion of the forward'stroke of the piston the exhaust port g is uncovered by the piston slightly in advance of the fuel When the exhaust port is thus uncovere the compressed s ent ases rush instantly from the center oft e cy inder into the central opening of the exhaust chamber in the piston and thence laterally through the side port of the same and then escape throu h the exhaust ort. Immediately after the exhaust ort as been uncovered by the piston and t e ressure of the spent gases in the cylinder has een relievedthe fuel inlet port f is also uncovered by the piston The fuel or gas under ressure 1n the crank chamber now enters the ower end of the guide-way or flue and is directed by the inclined bottom 41,

curved wall 11 of the piston and the curved bore of the cylinder inwardly and upwardly in a spiral path into the lower end of the cylinder. Upon reaching the upper endof the inclined bottom of the guide-way the aseous fuel passes over the bridge 9' above t e side opening of the exhaust chamber and continues its movement in a spiral path above the fuel inlet ort so as not to interfere with the inflow of uel The fresh fuel continues to move u wardly in a spiral path and sweeps the ore of the cylinder and when it reachesthe top thereof it 'radually fills the cylinder from the bore to t e center thereof,

- thereby displacing the s ent .gases and crowdin the latter gradua y from the bore of the cy inder toward the center thereof and out through the central exhaust in the piston. By this means the spent gases are exhausted first from the center of the cylinder Where they are hottest and at the same time the cylinder is cooled by the incoming fresh gases whereb undue heating of the engine is avoided, the ife of the same 1s prolonged and the running of the same is improved. c

Inasmuch as the fresh gas maintains a con- I stant whirling action around the spent gases and the latter move radially and axially outwardly under the pressure 'of the new incom ing gas the live and dead gases are divided into distinct zones whereby theliability of mixing the dead and live gases is reduced to a minimum, enabling the charges of fuel to be maintained practically pure, and rendering it possible to obtainthe maximum power therefrom. J

Owing to the spiral movement of the fresh gas in the cylinder around the burned as it is impossiblefor unburned gas to escape t ough the exhaust inasmuch as the unburned gas must travel the maximum distance in; the cylinder before reaching the exhaust and by the time it reaches this oint the exhaust is closed by the piston an the latter begins to compress the charge of new fuel.

Any suitable form of igniter k may be used that shown in the drawings being of the jump spark type and located in the cylinder,

so that the same is received by the front part of the fresh gas guide passage in the piston at the end of its compression stroke, whereby the igniter is certain of being surrounded by fresh gas and ignition of the same is posltively assured.

I claim as my invention:

. 1. A gas engine comprising a cylinder having a fuel port and an exhaust port, and a piston arranged in thecylin'der andhaving a spiral guide-way whereby the fuel is caused to whirl in said cylinder, substantially as set forth.

2. A gas engine comprising a cylinder having a fuel port in its side and a piston arranged in the cylinder and having a fuel guide-way which extends spirally around the periphery of the piston and is adapted to stand with its lower front end opposite said fuel port when the piston is in lts foremost position while its up er rear end terminates on the inner side of t episton, substantially as set forth.

3. A gas engine comprising a cylinder having a fuel port in its side, and a piston ar' ranged in said cylinder and having a s iral fuel guide-way the inclined bottom of w 'ch is arranged alon the eriphery of the piston and the side wal s of w ich are formed one on the piston and the other by the bore of the cylinder, and the lower end of said guideway being adapted to register with the fuel port, substantially as set forth.

4. A gas engine comprising a cylinder having fuel and exhaust orts in its side, and a piston arranged in said cylinder and having an exhaust conduit which opens centrally into the cylinder and adapted to communicate laterally with said exhaust ort and which is also provided with a spira fuel guide-way around said exhaust conduit which is adapted to register at its lower end with said fuel port while its up er end directs the fuel into the cylinder, su stantially as set forth.

5. A gas engine comprising a cylinder having fuel and exhaust ports in its side and circumferentially adjacent to each other, a piston having an exhaust conduit Which is proinner end where with the central art of the s ace in the oylof saidexhaust conduit and extending from 1.3 1

vided with an upper central opening on its elevated above the front end thereof, and a y the same communicates I bridge forming'the top of the lateral opening inder and which as a lower ateralopening the rear end of the guide-way to a point above adapted to register with said exhaust port, the front end thereof, substantially as set and said iston being also provided w1th a forth.

s iral fue guide-way between the periphery Witness my hand this 25th day of March,

0 the piston and said exhaust conduit which 1907. i is so constructed that the lower front end of HARRIS T. DUNBAR. said guide-way registers with, said fuel'port Witnesses:

in the foremost position of the piston while THEo. L POPl, the upper or;rear'end of said guide-way is ANNA HEIGIS. 

